Positively charged chrysotile asbestos fibers adhere to negatively charged sialoglycoproteins normally found on cell membranes, purportedly causing lysis of the cells. Previously, we labeled sialoglycoproteins on red cell membranes with a marker visible by electron microscopy (a lectin, wheat germ agglutinin (WGA) - conjugated to gold chloride (Au) spheres). Normally the Au-WGA complexes are distributed evenly on red cell surfaces. Our quantitative data show that the number of Au-WGA markers is significantly decreased on the surfaces of red cells which have been distorted during interaction with asbestos. WGA binds specifically to N-aetyl glucosamine (NAG), but non-specifically to N-acetyl neuraminic acid (NANA, a sialic acid). Thus, we pre-treated cells with neuraminidase and found that they were protected from distortion by asbestos. This corresponds with the original hypothesis that positively charged chrysotile asbestos binds to negatively charged sialic acid groups. Loss of the Au-WGA label subsequent to asbestos interaction suggests that this binding causes a depletion or redistribution of at least two sialoglycoprotein components (NAG and NANA). This is coincident with marked cell distortion and may be a basic mechanism through which chrysotile asbestos exerts its toxic effects upon a variety of cell.